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POWhy won't this printf() statement print two string variables in C?
 

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  1. POWhy won't this printf() statement print two string variables in C?
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    <p>I have been researching like mad while I learning C. I have been debugging a C program and I thought I had some major issues <a href="https://stackoverflow.com/questions/11747579/why-is-fgets-and-strncmp-not-working-in-this-c-code-for-string-comparison">here</a>. Now I have critical issues. I made a dummy program to print two strings in one statement as follows: </p> <pre><code> #include&lt;stdio.h&gt; int main(int argc, char* argv[]) { char *herp = "Derp"; char *derp = "Herp"; printf("Herp %s Derp %s\n", herp, derp); return 0; } </code></pre> <p>This prints out as expected. I get </p> <pre><code>Herp Derp Derp Herp </code></pre> <p>So, I thought, let me debug my own program by doing something similar. The following line in my program</p> <pre><code>printf("word is: %s and jumbled word is: %s\n", word, jumbleWord); </code></pre> <p>Should print out something like </p> <pre><code>Word is: word and jumbled word is: dowr </code></pre> <p>But it prints out something like</p> <pre><code>and jumbled word is: dowr </code></pre> <p><em>Where did the first part of the output go</em>? I need to be able to print these both on the same line to debug. Also, the fact that a statement like this is not working tells me that really weird things are going on and I am bald from tearing my hair out. As my linked posts indicates, I would eventually like to compare these string values, but how can I even do that if printf() is not working right? </p> <p>I am posting the entire program below so you can see where everything is happening. I am just learning how to use pointers. I originally had two pointers point at the same memory when I wanted to jumble a word and that didn't work very well! So I fixed that and got two separate memory spaces with the words I need. Now, I just can't print them. This all makes sense given the code below: </p> <pre><code>#include&lt;stdio.h&gt; #include&lt;stdlib.h&gt; #include&lt;string.h&gt; #define MAX_WORD_LENGTH 25 //Define global variables int numWords; //Preprocessed Functions void jumblegame(); void readFile(char *[]); void jumbleWord(char *); void guess(char *,char *); int main(int argc, char* argv[]) { jumblegame(); return 0; } void jumblegame() { //Load File int x = 5050; //Rows char *words[x]; readFile(words); //Define score variables int totalScore = 0; int currentScore = 0; //Repeatedly pick a random work, randomly jumble it, and let the user guess what it is srand((unsigned int)time(NULL)); int randomNum = rand() % numWords + 1; char source[MAX_WORD_LENGTH + 1]; char jumble[MAX_WORD_LENGTH + 1]; strncpy(source, words[randomNum], MAX_WORD_LENGTH + 1); strncpy(jumble, words[randomNum],MAX_WORD_LENGTH + 1); jumbleWord(jumble); guess(source, jumble); //printf("Random word is: %s\n ", words[randomNum]); //randomly jumble it } void readFile(char *array[5049]) { char line[256]; //This is to to grab each string in the file and put it in a line. int z = 0; //Indice for the array FILE *file; file = fopen("words.txt","r"); //Check to make sure file can open if(file == NULL) { printf("Error: File does not open."); exit(1); } //Otherwise, read file into array else { while(!feof(file))//The file will loop until end of file { if((fgets(line,256,file))!= NULL)//If the line isn't empty { int len = strlen(line); if (len &gt; 0 &amp;&amp; line[len - 1] == '\n') line[len - 1] = '\0'; array[z] = malloc(strlen(line) + 1); strcpy(array[z],line); z++; } } } fclose(file); numWords = z; } void jumbleWord(char *word) { int wordSize = strlen(word) - 1; //durstenfeld Implementation of Fischer-Yates Shuffle int i; int j; char temp; for(i = wordSize - 1; i &gt; 0; i--) { j = rand() % (i + 1); temp = word[j]; word[j] = word[i]; word[i] = temp; } } void guess(char *word, char *jumbleWord) { printf("original word is: %s\n", word); printf("jumbled word is: %s\n", jumbleWord); printf("source is: %s and jumbled word is: %s\n", word, jumbleWord); } </code></pre> <p>I think most people at this point would burn C and slap themselves for sucking so bad at it. However, I am going to keep trucking along. So let me apologize for any derp, but please know that I have spent many hours probably being really stupid and staring at this. I would love to say, "<em>Hey, C is so stupid because it won't do what I am telling it to</em>". Unfortunately, I can't believe this. I think it is doing exactly what I am telling it to do, but I am too close to this problem to see what I am doing wrong. </p> <p>As always, thank you for your help. My deepest respect, GeekyOmega</p>
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    1. COYou shouldn't call `srand` before each `rand`, but rather once at the start of the program.
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    2. COSide note: `char *jumbledWord= jumbleWord(jumble);`, you `jumbleWord` changes the string given as its argument itself. So `jumbleWord` and `jumble` will be the exact same thing after this call.
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      1. POWhy won't this printf() statement print two string variables in C?
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    3. COThanks Chris. I fixed that. Shahbaz, will fix that. I thought of a way where this might be redundant. As I said, new to pointers. :-) Still though, getting that bizarre problem. :-(
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      1. POWhy won't this printf() statement print two string variables in C?
      1. USGeekyOmega
 

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