Error must be a modifiable lvalue [closed] - c

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I'm trying to make a simple currency converter using C, but for some reason it keeps giving me the error "error must be a modifiable lvalue".
I have checked up my code, and I don't see any problems with it. Any help?
#include <stdio.h>
#include <stdlib.h>
void main(){
float jod_usd=1.41, usd_jod=0.71, jod_eur=1.26, eur_jod=0.8, currency;
char ic;
int f;
printf("Enter the number of your conversion option to continue...\n1- Convert from JOD\n2- Convert to JOD\n");
scanf("%d",&f);
printf("Enter the character of your second currency to continue...\nU - - USD\nE - - EUR\n");
scanf("%c",&ic);
printf("Enter your amount:\n");
scanf("%f",&currency);
if(f==1&&(ic='U'||ic='u')){
printf("%.2f JOD - - %.2f USD\n",currency,(currency*jod_usd));
}
if(f==1&&(ic='E'||ic='e')){
printf("%.2f JOD - - %.2f EUR\n",currency,(currency*jod_eur));
}
if(f==0&&(ic='E'||ic='e')){
printf("%.2f EUR - - %.2f JOD\n",currency,(currency*eur_jod));
}
if(f==0&&(ic='U'||ic='u')){
printf("%.2f USD - - %.2f JOD\n",currency,(currency*usd_jod));
}
system("pause");
}

Answer 1

TL;DR The mistake of using = instead of == caused this.
First, you're changing the value of ic unwantedly.
Second, due to operator precedence,
(ic='U'||ic='u')
is the same as
((ic='U'||ic) = 'u')
where, the result of (ic='U'||ic) is not an lvalue.

Answer 2

Are you sure it is not just a simple bug? You usually don't assign in a condition. If I fix that, then you get some program flow:
Enter the number of your conversion option to continue...
1- Convert from JOD
2- Convert to JOD
1
Enter the character of your second currency to continue...
U - - USD
E - - EUR
Enter your amount:
Code
#include <stdio.h>
#include <stdlib.h>
void main(){
float jod_usd=1.41, usd_jod=0.71, jod_eur=1.26, eur_jod=0.8, currency;
char ic;
int f;
printf("Enter the number of your conversion option to continue...\n1- Convert from JOD\n2- Convert to JOD\n");
scanf("%d",&f);
printf("Enter the character of your second currency to continue...\nU - - USD\nE - - EUR\n");
scanf("%c",&ic);
printf("Enter your amount:\n");
scanf("%f",&currency);
if(f==1 && (ic=='U' || ic=='u')){
printf("%.2f JOD - - %.2f USD\n",currency,(currency*jod_usd));
}
if(f==1&&(ic=='E'||ic=='e')){
printf("%.2f JOD - - %.2f EUR\n",currency,(currency*jod_eur));
}
if(f==0&&(ic=='E'||ic=='e')){
printf("%.2f EUR - - %.2f JOD\n",currency,(currency*eur_jod));
}
if(f==0&&(ic=='U'||ic=='u')){
printf("%.2f USD - - %.2f JOD\n",currency,(currency*usd_jod));
}
system("pause");
}