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POprint out a string in C
 

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  1. POprint out a string in C
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    <p>I'm at beginner level in C programming language. I'm trying to print out a string which its pointer is passed from a function to another pointer variable in main() function. My knowledge is very limited in C and I have looked up on the web (probably I have not look deep enough but please help) here is the code:</p> <pre><code>int i; char *result; result= center_string("I go to school everyday\nto study"); i=0; while (result[i]!='\0'){ printf("%c\n", result[i]); i++; } </code></pre> <p>and the result I received back are 4 weird characters arranged vertically (unfortunately stackoverflow.com does not let me post the picture)</p> <p>please help! thanks in advance</p> <p>-- added--- this is code for center_string:</p> <pre><code>static char* center_string(char* msg){ char toReturn[34]; // the return message has to contain two lines in one. It might be better to form this string while traversing two strings, rather than forming by the union of two lines char centerString[34]; // padding can be done during the process of splitting two lines or after. // it's harder to do while splitting two lines because the length of each line is unknown // countSecond starts with -1 because it contains \n which should not be in it. So this number will be discarded int paddingFirst = 0, paddingSecond = 0, countFirst = 0, countSecond = -1, countReturn = 0; // maximum number of return string is 34 // stillOnTheFirstLine is a boolean variable but representing by a integer with 1 digit int i = 0, stillOnTheFirstLine = 0; // start counting the character in the second line //initialize the return line for (i=0; i&lt;34; i++){ toReturn[i] = '\0'; centerString[i] = '\0'; // printf("initializing toReturn[%i] with value %c\n",i, toReturn[i]); } i = 0; while ( msg[i]!='\0' ) { // getting the first line to display // the limit is 16 chars or \n to the second line // i.e: I go to school e|very day\nto study // firstLine = "I go to school e" // secondLine ="to study" // discarded = "very day" // get the first line if (i&lt;=15 &amp;&amp; msg[i]!='\n'){ // this is the first line // insert the character into the return string toReturn[countReturn] = msg[i]; //printf("First line: %c\n", toReturn[countReturn]); countReturn++; countFirst++; }else{ // when the first line is finished // there are two cases // first case: when the first line is longer than 16 character long if (msg[i]!='\n' &amp;&amp; i&gt;15 &amp;&amp; stillOnTheFirstLine==0){ // discard the character //printf("Discard: %c\n", msg[i]); }else{ stillOnTheFirstLine = 1; // yes the parser is still on the second line // this is the second case which the first line is finished // check for 16 character instead of 15 because one of them is \n which separate line 1 and 2 if (countReturn&lt;33 &amp;&amp; stillOnTheFirstLine==1){ toReturn[countReturn] = msg[i]; // put the character from the msg string to the toReturn //printf("Second line: %c\n", toReturn[countReturn]); countReturn++; countSecond++; } // whatever after this is discarded } } i++; } // start padding paddingFirst = floor((double)(16-countFirst)/2); paddingSecond = floor((double)(16-countSecond)/2); // padding the first line i=0; while (toReturn[i]!='\0' &amp;&amp; toReturn[i]!='\n'){ centerString[paddingFirst] = toReturn[i]; paddingFirst++; i++; } // add '\n' into the centerString centerString[paddingFirst] = toReturn[i]; // then continue with the next character in toReturn i++; // padding the second line paddingSecond = i+paddingSecond; while(toReturn[i]!='\0'){ centerString[paddingSecond] = toReturn[i]; paddingSecond++; i++; } /*for(i=0; i&lt;34; i++){ printf("the result string is: %c\n", centerString[i]); }*/ return centerString; </code></pre> <p>}</p>
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    1. USMatthew Manela
    1. USTri
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    1. COwhat is `center_string`?
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      1. POprint out a string in C
      1. USNathan Fellman
    2. COyou're returning a pointer to a temporary variable (`centerString[34]`) that goes out of scope when you return from `center_string()`. the pointer then points to garbage, which is what you're printing out. a quick fix is to declare the variable as `static`, as in `static char centerString[34];`.
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