Compilare: user.c: In function ‘main’: user.c:24:9: warning: implicit declaration of function ‘strcat’ [-Wimplicit-function-declaration] strcat(A, buf); ^ user.c:24:9: warning: incompatible implicit declaration of built-in function ‘strcat’ [enabled by default] user.c:25:9: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration] poz += strlen(buf); ^ user.c:25:16: warning: incompatible implicit declaration of built-in function ‘strlen’ [enabled by default] poz += strlen(buf); ^ user.c:26:9: warning: implicit declaration of function ‘strcpy’ [-Wimplicit-function-declaration] strcpy(buf,""); ^ user.c:26:9: warning: incompatible implicit declaration of built-in function ‘strcpy’ [enabled by default] user.c:32:5: warning: implicit declaration of function ‘strtok’ [-Wimplicit-function-declaration] p = strtok(buf," \n"); ^ user.c:32:7: warning: assignment makes pointer from integer without a cast [enabled by default] p = strtok(buf," \n"); ^ user.c:33:5: warning: incompatible implicit declaration of built-in function ‘strcpy’ [enabled by default] strcpy(B,p); ^ user.c:41:18: warning: incompatible implicit declaration of built-in function ‘strlen’ [enabled by default] if(ok == strlen(B)) ^ user.c:31:10: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(buf,7,pf); ^