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PO
 

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  1. PO
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    <p>I don't know your binary file format. Your code tell the binary file have names only with 30 characters.</p> <pre><code> struct alu{ int cod; char name[30]; //juan - pedro - leo int sex; }; </code></pre> <p>This structure size is not 38 bytes.</p> <p>Check structure size.</p> <pre><code>printf("%d", sizeof(struct alu)); </code></pre> <p>structure size depend on your compiler option...</p> <p>If your binary format has bellow format.</p> <pre><code>{ // 1st record cod = 10 names[30] = "juan" sex = 1 } { // 2nd record cod = 20 names[30] = "pedro" sex = 1 } { // 3rd record cod = 12 names[30] = "leo" sex = 2 } </code></pre> <p>See your code.</p> <pre><code>#include &lt;stdio.h&gt; #pragma pack(push, 1) or 4 or 8 depend on your binary format. struct alu{ int cod; char name[30]; //juan - pedro - leo int sex; }; #pragma pack(pop) int FSearch(char path[],char X[]) { char Name[30]; struct alu A; FILE *arc; arc=fopen(path,"rb"); //fseek(arc,sizeof(char[30]),SEEK_SET); fseek(arc,0,SEEK_SET); // first record. //while (fread(Name,sizeof(char[30]),1,arc)) { while (fread(A,sizeof(A),1,arc)) { /*Here is when the errors happen.. The next sentence tell me that A.name don't have the name from the second time*/ printf("%s and %s.",X,A.name); if (strcmp(A.name,X)==0) { printf("Information of %s:\n",X); //fshow_str(A); fclose(arc); return 1; // found } } fclose(arc); return 0; // not found } int main(int argc, char **argv) { char path[]="file.bin"; printf("\n%d",FSearch(path,"pedro")); return 0; } </code></pre> <hr> <p>cod size depend on compiler OPTION!!!</p> <pre><code>int FSearch(char path[],char X[]) { char Name[30]; struct alu A; FILE *arc; arc=fopen(path,"rb"); fseek(arc,0,SEEK_SET); // first record. //while (fread(Name,sizeof(char[30]),1,arc)) { while (1) { //if ( -1 == fseek(arc,4,SEEK_CUR)) // Important!!! case structure pack(4) for skip cod or // break; if ( -1 == fseek(arc,8,SEEK_CUR)) // Important!!! case structure pack(8) for skip cod break; if (!fread(Name,sizeof(Name),1,arc)) break; A.name = Name; /*Here is when the errors happen.. The next sentence tell me that A.name don't have the name from the second time*/ printf("%s and %s.",X,A.name); if (strcmp(A.name,X)==0) { printf("Information of %s:\n",X); //fshow_str(A); fclose(arc); return 1; // found } } //if ( -1 == fseek(arc,4,SEEK_CUR)) // Important!!! case structure pack(4) for skip sex or // break; if ( -1 == fseek(arc,8,SEEK_CUR)) // Important!!! case structure pack(8) for skip sex break; fclose(arc); return 0; // not found } </code></pre> <hr> <p>Binary file and structure are alined with 4 bytes.</p> <pre><code>// Attention! pragma pack(push, 4) needs!!! // Your now running machine is 32 bits system. // This source code will invoke addressing fault 64 bits NON Intel processor. #pragma pack(push, 4) // align 4 bytes. struct alu{ int cod; // Integer type. 4 bytes on 32bits system. but 8 bytes on 64 bits system. // I recommend using "long" type. "long" type is 4 bytes on any system. char name[30]; //juan - pedro - leo int sex; // also, Integer type. }; #pragma pack(pop) int FSearch(char path[],char X[]) { char Name[30]; struct alu A; FILE *arc; arc=fopen(path,"rb"); fseek(arc,0,SEEK_SET); // first record. //while (fread(Name,sizeof(char[30]),1,arc)) { while (1) { if ( -1 == fseek(arc,4,SEEK_CUR)) // Skip "cod" 4 bytes. break; if (!fread(Name,sizeof(Name),1,arc)) // Read "name" 30 bytes. break; if ( -1 == fseek(arc,2,SEEK_CUR)) // Skip "name"'s aligned 2 bytes. break; A.name = Name; /*Here is when the errors happen.. The next sentence tell me that A.name don't have the name from the second time*/ printf("%s and %s.",X,A.name); if (strcmp(A.name,X)==0) { printf("Information of %s:\n",X); //fshow_str(A); fclose(arc); return 1; // found } } if ( -1 == fseek(arc,4,SEEK_CUR)) // Skip "sex" 4 bytes. break; fclose(arc); return 0; // not found } </code></pre>
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    1. POThis algorithm doesn't work
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      1. PTQuestion
    1. PTAnswer
    1. USbooiljoung
    1. USbooiljoung
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    1. COI've update my ask.. Your answer work but is not my goal use a structure to read but: read a string, condition, fseek.. read a string, condition.. I have declared the structure for explanatory purposes. And your binary file format is correct.
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      1. PO
      1. USLucio
    2. COYou should know your binary pack size. pack(1), record.cod size is 4 bytes. pack(2), record.cod size is 4 bytes. pack(4), record.cod size is 4 bytes. pack(8), record.cod size is 8 bytes. So you should read a record... This is safer way.
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      1. USbooiljoung
    3. COif pack size is 4 bytes. I will append more code.
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      1. USbooiljoung
 

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