Compilare: user.c: In function ‘expr’: user.c:67:9: warning: implicit declaration of function ‘strchr’ [-Wimplicit-function-declaration] for( x = expr(lev+1); strchr(op[lev], *p); x = y ) ^ user.c:67:31: warning: incompatible implicit declaration of built-in function ‘strchr’ [enabled by default] for( x = expr(lev+1); strchr(op[lev], *p); x = y ) ^ user.c: In function ‘eval’: user.c:33:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘main’: user.c:73:10: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets( S, NX, fopen( "evaluare.in", "r" ) ); ^