Let the student management system, how to judge the user input the wrong, let him enter again?
While (the scanf (" % d ", & amp; Num==0)
{
Printf (" format error, please enter again: ");
fflush(stdin);
}
This kind of writing can't check his Numbers as the beginning of the random input, such as: 15 DQW $@ # this, o great god to give a solution to the rigorous check his input

CodePudding user response:

Try using a regular expression, the digital \ d

CodePudding user response:

Use getchar (), one by one analysis, found illegal, will prompt,
If the legitimate, joining together own figures, string, etc.,

CodePudding user response:

Please refer to the "c + + console program to determine input digital"
Wish I could help you!

CodePudding user response:

Fyi:

//input two integers 
#include  
Int main () 
{
Int a, b, n, v, r, k; 
Char buf [80]. 
Char * p; 

K=0; 
R=EOF. 
While (1) {
If (EOF==r) {
The fgets (buf, 80, stdin); 
P=buf. 
} 
While (1) {
R=sscanf (p, "% d % n, & amp; V, & amp; n); 
If (1==r) {k++; break; } 
If (EOF==r) break; 
p++; 
} 
If (EOF==r) continue; 
P +=n; 
If (1==k) a=v; 
If (2)==k {
B=v; 
break; 
} 
} 
Printf (" % d, % d \ n ", a, b); 
return 0; 
} 

 # include & lt; stdio.h> 
Char [] s="123 ab 4"; 
Char * p; 
Int n, n, k; 
Void main () {
P=s; 
While (1) {
K=sscanf (p, "% d % n, & amp; V, & amp; n); 
Printf (" k, v, n=% d, % d, % d \ n ", k, v, n); 
If (1)==k {
P +=n; 
{} else if (0==k) 
Printf (" skip char [c] % \ n ", p [0]). 
p++; 
} else {//EOF==k 
break; 
} 
} 
Printf (" End. \ n "); 
} 
//k, v, n=1123, 
//k, v, n=0123, 
//the skip char [] 
//k, v, n=0123, 
//the skip char [a] 
//k, v, n=0123, 
//the skip char [b] 
//k, v, n=1,4,2 
//k, v, n=1,4,2 
//End.