There is a slight error in the program. A==b==c is incorrect. It should be written as a = = b&; & ampA==c, otherwise the program cannot judge the equilateral triangle.
# include & ltstdio.h & gt
# include & ltmath.h & gt
int main()
{
baidouble a、b、c；
printf("Please Old2 input a，b，c:\ n ")；
Scanf("%lf%lf%lf ",& one, & c)；
If (A>0 & AMPB & GT0 & AMPC & GT0 & AMPA+B > c & amp& ampa+c & gt； b & amp& ampb+ c & gt； answer
{
duif(a = = b & amp； & ampb==c)
Printf ("equilateral triangle zhi");
else if(a = = b & amp； & Answer! = C || A = = C & Answer! = b | | b = = c & amp& ampb！ =a)
Printf ("isosceles triangle");
else if(a * a+b * b = = c * c | | b * b+c * c = = a * a | | a * a+c * c = = b * b)
Printf ("right knife triangle");
else if(a = = b & amp； & Answer! = C || A = = C & Answer! = b | | b = = c & amp& ampb！ = b & amp& ampa * a+b * b = = c * c | | b * b+c * c = = a * a | | a * a+c * c = = b * b)
Printf ("isosceles right triangle");
other
Printf ("general triangle");
}
other
Prinf ("old2 stupid! ! ! \ n ")；
Returns 0;
}
Extended data:
The general form of the if statement is as follows:
If (expression) statement
[else statement]
The "expression" in the if statement can be relational expression, logical expression or even numerical expression. Among them, relational expression is the most intuitive and easy to understand. The so-called relationship is a formula for comparing two numerical values.
If-else statement introduces an ambiguity problem else (dangling -else problem), which appears when there are more if clauses than else clauses. The question is which if clause these else clauses match respectively.
Baidu encyclopedia -if statement